Changed occurrences of "busy-level" to "busylevel" in sip.conf.sample

in light of commit 89441. Thanks to pj for pointing out the need for this

(closes issue #11307, reported by pj)



git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@89453 65c4cc65-6c06-0410-ace0-fbb531ad65f3